The invention relates generally to power-driven conveyors and more particularly to modular plastic conveyor belts with article-supporting rollers.
Article-supporting rollers are used in modular plastic conveyor belts to provide low-friction rolling support to conveyed articles. In many roller-top belts, the rollers are mounted on steel axles in cavities formed in the belt modules used to construct the modular belt. Because of the presence of the cavities, the plastic modules are less stiff than they would be without the cavities. Wide roller-top belts with many cavities require more underlying support area, e.g., more wearstrips, across the width of the conveyor. More wearstrips can mean higher costs in materials and construction, more friction between the belt and the wearstrips, and increased obstruction to air flow through the belt. Thus, there is a need to minimize the support surface area required to support roller-top belts across their widths.
Roller-top belt modules with steel axles are more difficult to manufacture than standard modules without rollers. One way to manufacture a roller-top module is to injection-mold the module around a roller on a steel axle. The ends of the axle extend into the mold and are encapsulated in the molded module body. Another way is to injection-mold a module body with a receptacle for a roller. Then, in a secondary manufacturing step, a roller and axle are placed in each receptacle, and a cover is welded or otherwise retained in place over the ends of the axle to hold the roller in the module. Thus, there is a need to simplify the manufacture of roller-top belts.